The move comes as the United States, China, Russia, Japan and the two Koreas scrambled to arrange a new round of negotiations on the topic, with South Korea and Russia saying they are unlikely this month.
North Korea has said before it is willing to freeze its "nuclear activities" in exchange for U.S. aid and being removed from Washington's list of terrorism sponsoring nations.
On Tuesday, it specified it was "set to refrain from test and production of nuclear weapons and stop even operating nuclear power industry for a peaceful purpose as first-phase measures of the package solution."
In a commentary carried by the official KCNA news agency, North Korea called the offer "one more bold concession."
Washington has said it wants North Korea to verifiably begin dismantling its nuclear weapons programs before it delivers any concessions.
Meanwhile, a delegation of Americans left for the communist country to possibly tour a disputed nuclear plant.
The unofficial delegation of Americans, which included a former government official and a retired academic, flew from Beijing to North Korea to possibly tour the communist country's disputed nuclear plant at Yongbyon.
Members of the group refused comment on reports that they might visit the Yongbyon complex.
"It's a very private visit. We're not representing the U.S. government or anyone else," said Jack Pritchard, once a member of former President Bush's National Security Council staff and a one-time State Department official.
Pritchard resigned in August after getting criticized for taking too soft a line toward the North.
A South Korean Foreign Ministry official said on condition of anonymity that the group was to stay in the North from Tuesday to Saturday. Another pair of Americans, both congressional staffers, also were scheduled to visit Pyongyang this week.
The Yongbyon complex is at the heart of the standoff, and there has been no outside access to the facility since North Korea expelled U.N. nuclear inspectors at the end of 2002.
On Tuesday, North Korea said its first-step proposal should be the focus of preparations for new talks.
"If the United States keeps ignoring our efforts and continues to pressurize the DPRK to scrap its nuclear weapons program first while shelving the issue of making a switchover in its policy toward the DPRK, the basis of dialogue will be demolished and a shadow will be cast over the prospects of talks," KCNA said.
DPRK stands for Democratic People's Republic of Korea, North Korea's official name.
South Korea's Unification Ministry, which handles affairs with North Korea, says North Korea has at least three nuclear reactors.
Last year, it restarted a five-megawatt reactor at Yongbyon. An unfinished 50-megawatt reactor also stands at Yongbyon, and a 200-megawatt one is located just northeast of the site at Taechon.
A U.S.-led international consortium had been building two 1,000-megawatt light-water reactors on the country's east coast. But that project was suspended last month amid the nuclear standoff.
North Korea's neighbors were suspicious of the intent behind North Korea's other nuclear reactor and agreed to help build the light-water ones because they are more difficult to convert to weapons use. North Korea's offer to suspend all nuclear activities, even those for peaceful purposes, could be aimed at easing those suspicions.
A first round of talks including the two Koreas, the United States, China, Russia and Japan in Beijing in August ended with little progress.
There were hopes a new six-nation round could open early this year. But Russian and South Korean officials said Monday that talks probably would not happen this month, citing differences between the Washington and Pyongyang as well as scheduling difficulties around the Russian Christmas holiday and the Chinese Lunar New Year, both of which come in January.
The North Korean nuclear crisis flared in October 2002 when U.S. officials accused North Korea of running a secret nuclear weapons program in violation of a 1994 deal in which North Korea is obliged to freeze its nuclear facilities. Washington and its allies cut off free oil shipments, also part of the 1994 accord.
North Korea claimed it needed nuclear weapons because of the Bush administration's policy of "preemptive" war in Iraq and President Bush's labeling North Korea part of an "axis of evil" along with Iraq and Iran.
Pyongyang has demanded bilateral talks with the United States and wants a nonaggression pact with Washington.
The Bush administration insisted on multiparty negotiations, but Mr. Bush recently offered written security guarantees to the North. The president has consistently denied any intention of invading North Korea.